1. When Jennifer Aniston left Los Angeles for the filming, she fell off an escalator at the airport

London's media was splashed with photos of it the minute she touched down in London. Matthew Perry later apologied for not running to help - he was preoccupied with photgraphers, desperate to find out who was going to marry who in the critical episode!

2. Joey and Chandler were originally going to visit a London McDonald's - but it got replaced with Joey 'going into the map'

in the original script, Joey and Chander bickered a whole lot more - but it was condensed down to make room for the scene with Fergie, the Duchess of York.

3. The scene with Richard Branson, or 'Tricky Dick' took TONS of takes to get right because Richard Branson couldn't remember his lines

Warner Bros via NBC

The real-life wheeler dealer came to filming straight from an important meeting with the Prime Minister of Israel and didn't have time to learn his lines! If you look over Joey's shoulder when they are at the hat stand, there is a red baseball cap displaying the Virgin logo.

4. Changes had to be made to Emily's wedding dress because her boobs grew

5. Sarah Ferguson, the Duchess of York, was a total wreck during filming

Fergie was super-nervous during filming (her daughters Eugenie and Beatrice were obsessed with Friends), so much so that Matt Le Blanc had to go over her lines with her and Matthew Perry stayed behind to offer his support. Could they BE any cuter?!

6. The producers went to a LOT of trouble to keep the ending a secret

Warner Bros via Comedy Central

They briefed the cast not to give ANYTHING away, and even evacuated the studio audience before they filmed the real ending, where Ross says Rachel at the altar!

7. But then Elliot Gould (aka Jack Geller) nearly ruined all their hard work

When he returned from filming Ross and Emily's wedding in London, he went on Rosie O'Donnell's show, not realising how top secret the plot was. He said WAY too much about who Ross ended up marrying and producers were furious with him.

8. Lisa Kudrow covered for him in an interview, saying they'd filmed THREE endings to throw the press (and fans!) off the scent

This wasn't true, but provided a little damage control - there was still a cliffhanger at the end of the season, so fans had to tune in to Season Five to see what happened after Ross's slip-up.

9. There was originally an entire scene where Rachel reupholsters a couch in an effort to get over Ross

Warner Bros via Comedy Central

Script writer Greg Malins said: 'It just wasn't funny. This was at the end of the season and we're in the writers room at five in the morning... and when you haven't slept in two days, that seems really funny. Then you go see it and you go, "Boy, we were tired!". But I think cutting it [the couch scene] is what made the 'London, baby!' stuff with Joey evolve - which was hilarious.'

10. A rumour went around that the Queen banned the Friends crew from filming in front of Buckingham Palace because she was unhappy with something Fergie said on Oprah Winfrey's chat show

Actually, the Palace administration allows NO filming of the Queen's residences unless it's for a documentary or a news story - there could be no exceptions, even for the Queen's former daughter-in-law Fergie.

11. London radio stations revealed where filming was taking place and the cast were mobbed by fans

Channel 4 erected crush barriers outside their building to hold back fans when the cast arrived for a press conference. If the fans at this year's Friends Fest were anything to go by, we can only imagine the chaos!

12. Ross and Emily's marriage was originally planned to last

But Helen Baxendale did not wish to remain in America while pregnant. The writers couldn't think of a convincing story for why Emily would not be in the show, despite being married to Ross, so Baxendale was written out in the next season (and the rest is history).

13. The reaction when Monica and Chandler emerged from under the bed covers was SO crazy, the actors had to hold their position for 27 seconds to get the shot

The crew ended up ordering 400 pizzas for the audience because filming went on so long.

14. Lisa Kudrow was so heavily pregnant during filming, doctors actually ordered her not to fly

Warner Bros via Comedy Central

That was the reason Phoebe couldn't join in the fun - producers had to find a way to keep her in London for the episode, so timed her pregnancy with the triplets accordingly. Kudrow ended up giving birth to her son the day the second part of the episode was aired.

15. The writers messed up Joey's best man speech

Warner Bros via Comedy Central

During his best man speech at the rehearsal dinner, Joey says "I first met Ross in this coffee house back home...", but we learned in The One With The Flashback that Joey met Ross in the BAR (that eventually became the coffee shop). D'oh.

16. And finally, prepare for your mind to be blown. This is a big one. THEY FORGOT TO INVITE BEN